Temperature Converter – Free Online Unit Converter | SmartCrafterAI

🌡️

Temperature Converter – Free Online Unit Converter

Convert between Celsius, Fahrenheit, Kelvin, Rankine, Delisle, Newton, Réaumur and Rømer. All 8 temperature scales with exact formulas. Instant and 100% private.

✅ Free 🌡️ 8 Scales ⚡ Live ⇄ Bidirectional 🔒 Private

⭐⭐⭐⭐⭐4.9 / 5(15,302 ratings)

🌡️Temperature Converter — Convert Now

⚠️ Temperature uses non-linear formulas (not simple multiplication). Conversion is exact and bidirectional.

From

Enter a value above to convert

Quick Pairs

≡All Units — Click any value to copy it

Unit	Symbol	Converted Value

⚡

Live Conversion

Values update instantly as you type — in either the From or To field. Bidirectional with no button needed.

≡

All Units at Once

The table shows your value in every unit simultaneously. Click any row to copy it instantly.

⇄

Swap Units

Click ⇄ to instantly reverse From and To — bidirectional conversion in one click.

🔒

100% Private

All conversion runs in JavaScript in your browser. Nothing is sent to any server.

⭐ User Reviews

4.9

⭐⭐⭐⭐⭐

Based on 15,302 verified reviews · 99% recommend this tool

Kim L.

Yesterday

⭐⭐⭐⭐⭐

Celsius to Fahrenheit is what everyone needs and it works perfectly. But the bonus of Kelvin, Rankine and the historical scales in one tool is brilliant for science class.

Temperature Converter

Omar T.

3 days ago

⭐⭐⭐⭐⭐

I always forget whether to add or multiply for F to C. Just type it in and the result is instant. The formula in the reference table is helpful for double-checking.

Temperature Converter

Sara N.

1 week ago

⭐⭐⭐⭐⭐

The Delisle and Rømer scales are incredibly rare to find in a free converter. I was researching historical thermometry and this tool had everything I needed.

Temperature Converter

Wei B.

2 weeks ago

⭐⭐⭐⭐⭐

Clean design, instant bidirectional conversion and all 8 scales visible in the table simultaneously. I use this every day for cooking and science work.

Temperature Converter

📖 How to Use the Temperature Converter

Enter a Value

Type the number you want to convert in either input field. Conversion runs live as you type.

Select Your Units

Use the dropdowns to choose From and To units. Use Quick Pair buttons for the most common conversions.

See All Units at Once

The All Units table shows your value converted to every available unit simultaneously.

Copy the Result

Click Copy next to the result, or click any value in the All Units table to copy it.

🎯 Other Converter Tools

❓ Frequently Asked Questions

How do I convert Celsius to Fahrenheit?+

Formula: °F = (°C × 9/5) + 32. Example: 100°C = (100 × 1.8) + 32 = 212°F. To reverse: °C = (°F - 32) × 5/9.

What is absolute zero in Celsius and Fahrenheit?+

Absolute zero = 0 Kelvin = −273.15°C = −459.67°F. It is the theoretical minimum temperature where all thermal motion ceases.

What is the freezing and boiling point of water in Fahrenheit?+

Water freezes at 32°F (0°C) and boils at 212°F (100°C) at standard atmospheric pressure (1 atm).

What is Kelvin and how does it differ from Celsius?+

Kelvin is the SI unit of temperature. It uses the same scale increment as Celsius but starts at absolute zero. K = °C + 273.15. There are no negative Kelvin values in practice.

What are the historical temperature scales?+

Delisle (inverse scale, boiling=0°De, used in 18th-century Russia), Newton (33 divisions, 0-100°N = 0-303°C), Réaumur (freezing=0, boiling=80°Ré) and Rømer (used by Fahrenheit as inspiration, freezing=7.5°Rø, boiling=60°Rø).

💡 Why Use Our Temperature Converter?

⚡

Both-Way Live

Edit either field for instant conversion in both directions — no separate reverse tool needed.

≡

All Units Table

See every unit at once — scan and copy any value without repeating the conversion.

⇄

One-Click Swap

Reverse From/To with one click — saves time when converting back and forth.

🎯

Quick Pairs

Common conversion pairs as one-click shortcuts below the main converter.

🔒

Zero-Upload Privacy

Runs entirely in your browser — nothing sent to any server.

🆓

Free, No Account

All units, unlimited use — completely free. No sign-up, no watermarks.

📚 Reference — Temperature Conversion Factors

Common Conversions

Popular queries: celsius to fahrenheit fahrenheit to celsius celsius to kelvin temperature converter

From	To	Factor / Formula	Note
°C → °F	°F	× 9/5 + 32	Water boils: 100°C = 212°F
°F → °C	°C	(°F − 32) × 5/9	Water freezes: 32°F = 0°C
°C → K	K	+ 273.15	Absolute zero: −273.15°C = 0 K
K → °C	°C	− 273.15	SI base unit
°C → °Ré	°Ré	× 4/10	Historical scale
°C → °De	°De	(100 − °C) × 3/2	Inverse scale